:root { color-scheme: light dark; }
body {
  margin: 0;
  font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Helvetica Neue", sans-serif;
  background: Canvas;
  color: CanvasText;
}
main { max-width: 640px; margin: 0 auto; padding: 48px 16px; }
h1 { font-size: 1.8rem; margin-bottom: 0.5rem; }
h2 { font-size: 1.15rem; margin-top: 2rem; }
a { color: #0a84ff; }